Servlet实现文件下载
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2022-05-24 20:51:09
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<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
(图片)<a href="/day03/download?filename=r1.jpg">下载</a><br/>
</body>
</html><servlet>
<description></description>
<display-name>UploadFile</display-name>
<servlet-name>UploadFile</servlet-name>
<servlet-class>xinfei.code.file.UploadFile</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UploadFile</servlet-name>
<url-pattern>/uploadFile</url-pattern>
</servlet-mapping>public class UploadFile extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//获取要下载的问价名称
String filename = request.getParameter("filename");
//获取上下文对象
ServletContext context = getServletContext();
//获取要下载文件的类型
String mimeType = context.getMimeType(filename);
//设置文件下载头
String agent = request.getHeader("user-agent");
//如果是中文可能会有编码问题 这里会使用一个工具类
String f_name = new Date().toString();
f_name = DownLoadUtils.getName(agent, f_name);
response.setHeader("content-disposition", "attachment;filename="+f_name+".jpg");
//设置流
ServletOutputStream os = response.getOutputStream();
InputStream is = context.getResourceAsStream("/download/"+filename);
IOUtils.copy(is, os);
//关流
is.close();
os.close();
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}编码工具类
public class DownLoadUtils {
public static String getName(String agent, String filename) throws UnsupportedEncodingException {
if (agent.contains("Firefox")) {
//火狐浏览器
BASE64Encoder base64Encoder = new BASE64Encoder();
filename = "=?utf-8?B?" + base64Encoder.encode(filename.getBytes("utf-8")) + "?=";
} else {
//其他浏览器
filename = URLEncoder.encode(filename, "utf-8");
}
return filename;
}
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